Resection Volume

Can anyone help me with how the Resection Volume plugin works?
I am not able to find any tutorial for the plugin only some screenshots of the output on the documentation.
As it mentioned I added 4 point list on the model to generate a label map but the plugin only takes 1 point list at a time.
I don’t know if there is a way to merge all point list to 1 label and give it as input to generate the 3D surface.

Apologize, if its some basic steps and am unaware about it.

It would be really helpful, if someone has already worked on this plugin could help me.